Rolling method for wire and other rod-shaped rolling stock

ABSTRACT

Rolling method and roller train for making wire and other rodshaped rolling stock of circular cross-section and nearly circular cross-section such as polygonal cross-section, according to which a plurality of successive oval passes not offset with regard to each other are followed by a plurality of compression or round passes which while not offset with regard to each other are offset by 90* with regard to said preceding oval passes.

United States Patent- Dechene et al. 51 Aug. 15, 1972 ROLLING METHOD FOR WIRE AND [56] References Cited 3:33: ROD-SHAPED ROLLING UNITED STATES PATENTS 2,369,730 2/1945 Fisk ..72/235 Inventors- Walter Dechene, g Herbert 3,566,657 3/1971 Blinn ..72/234 Rothe, Hagen-Emst; Fritz Salmen, I Herdecke/Ruhr, all of Germany Primary Examiner-Lowell A. Larson [73] Assignee: Stahlwerke Sudwestfalen AG, Hut- Attorney-Walter Becker tental-Geisweid, Germany 57] ABSTRACT [22] Filed: June 1970 Rolling method and roller train for making wire and [211 App} 50 597 other rod-shaped rolling stock of circular cross-section and nearly circular cross-section such as polygonal cross-section, according to which a plurality of succes- [52] US. Cl ..72/235, 72/366 give oval passes not offset with regard to each other [51] Int. Cl. ..B21bl/l8 are followed by a plurality of compression or round [58] Field of Search ..72/234, 235, 365, 366 passes which while not offset with regard to each other are offset by 90 with regard to said preceding oval passes.

8 Claims, 2 Drawing; Figures 3 4 I Z 3 4 3 l i PATENTEBMIB 15 I972 3.683.662

sum 1 or 2 lnvenlors ROLLING METHOD FOR WIRE AND OTHER ROD- SHAPED ROLLING STOCK The present invention relates to a rolling method for producing wire and other rod-shaped metallic rolling stock, especially with high exit speeds in excess of 20 millimeters per second and small final dimensions below 100 m It is an object of the present invention to provide a new rolling method which will make it possible in an economic and operation-safe manner to produce metallic rod-shaped rolling stock having a high surface quality, precision as to dimensions, in other words, low tolerance, and a high hourly output while securing a thin cross section. I

It is another object of this invention to provide a method as set forth in the preceding paragraph, which will permit the economic and safe production of metallic rod-shaped rolling stock, especially of high grade steel and other high grade metallic substances while the above requirements must be met also if it is desired to process in fast sequence materials which have a different behavior as to deformation.

The term high grade steel and similar alloys includes steels and alloys which, due to their alloy content, have high strength at the temperatures of deformation.

The above outlined objects and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 diagrammatically illustrates in plan view a rolling frame according to the invention.

FIG. 2 illustrates the calibrating diagram pertaining thereto.

It is well-known for purposes of rolling rod-shaped rolling stock, especially wire, to employ different calibrating series. 1

Thus, it is known to roll:

Diamond square oval round Oval square oval round Oval round oval round Oval upset (Staucher) oval round Oval oval oval round Pointed arch pointed arch round In this connection, reference may be had to:

1. German Pat. No. 747,81 1

2. German Pat. No. 818,789

3. German Pat. No. 1,140,533

4. German Auslegeschrift 1,189,040

5. German Auslegeschrift 1,269,980

6. German Auslegeschrift 1,282,582

In all of these shaping methods, the rolling stock is either twisted from stand to stand or is formed in alternately horizontal and vertical stands to smaller surfaces. The purpose of this way of operation consists in obtaining also large decreases in the surfaces (from 10 to 30 percent) by large decreases in the height (20 percent) therefore twisting, upwardly placing of the oval in square or round caliber.

In order with the above mentioned shaping method to increase the output and to lower the manufacturing costs, the technical development during the last 20 years has followed the following principles (see Drahtwelt 54/1968 pages 609-614 and pages 669-676):

1. Increase in the output speed up to 60 meters per second.

2. Multi-core rolling (up to 4 cores).

3. More powerful driving motors, if necessary individual drives and thereby increase in the number of motors.

4. More rigid rolling stands as conditioned for higher deformation work which with great decrease in the surface (multi-core rolling) and high rolling speed is to be absorbed by the rolling stand.

5. Mechanization ,of the entire :rolling operation and in particular the guiding of the rolling stock. Inasmuch as with high rolling speeds, the previously customary manual introduction is not feasible on one hand, while on the other hand, a faulty first pass causes considerable interference and idling periods of the expensive installation, the rolling stock was, prior to being introduced into the rolling train, guided automatically up to its exit.

7 6. Automation of the installation by expensive controlling and setting devices (power and speed control of all driving motors, loop control, rolling stock control (for instance, temperature and dimensions) between the individual stands.)

7. Increase in the ring weights (Ringgewichte) up to 1,200 kilograms.

8. Adoption of smaller roller diameters to roller pressure and torque.

These steps were substantially successful with ordinary steel. Accordingly, four-core wire trains with monthly outputs of wire of approximately 40,000 tons and a diameter of 5.5 millimeters are in production. A special development during the last 10 years concerns the introduction of rolling blocks (see for instance German Auslegeschrift 1,269,980) according to which from six to 10 deforming stands are in one block driven by a common drive with predetermined transmission ratios. This method is intended to reduce investment costs and operational costs (elimination of driving motors and control and setting devices) and furthermore to secure a reduction in the setting, idle and servicing time. Also with these blocks, the deformation steps cor respond to the above outlined prior art.

All heretofore known rolling methods involve con siderable operational difficulties and limitations when the surface quality of the rolling stock being produced has to meet high requirements and/or when the same installation has to process materials with different resistance to the deformation of the respective material. With mass or ordinary steels, the requirements as to the surface of the rolled goods or stock are less in view of the secondary purpose of employment and in view of the normally successive cold drawing operation. With high-grade steels, however, roughness, caused for instance by rough calibers or a looping of the rolling stock at the rolling stock guiding means as well as similarly caused tears and scale formation bring about considerably waste. Consequently, more modern wire trains for high grade steel which process rolling stock under the above mentioned conditions, proceed in the following manner:

1. Doing away with multi-core rolling (as a rule rolling with one core only and exceptionally with two cores.

2. Doing away with rolling blocks, i.e. with rigid drives for a plurality of stands.

3. \lVith high grade steel, the decrease in the surface per stand is limited. Whereas, with cross sections reduce the of approximately 100 mm the decrease in surface is limited to approximately 20 percent per stand, the maximum possible decrease in surface when rolling cross sections below 100 mm drops even to 12 percent. For extremely high grade material with difficult rolling methods, these values drop even further. In view of the low surface decrease per stand, high grade steel trains have with the same total deformation, a higher number of stands than corresponding ordinary steel trains. Correspondingly, also the expenses for mechanical and electrical parts, the requirement of space and the investing and operational costs increase accordingly.

4. Lowering of the rolling speed from ordinary steel to high grade steel by more than 40 percent.

5. When effecting a quality and dimensional change, new test driving and controlling of the train by test rolling is required (bringing about a poor discharge and unsatisfactory exploitation of time.

6. Longer billet moving time in view of the lower rolling speed increase difficulties, and additional means are necessary for controlling uniform temperatures over the length of the billets and all rolling stands. As a result, limitation of the ring weights when processing high grade steel over ordinary steelentails.

7. The difficulties set forth above under 6 also harm fully affect high grade steel as far as the tolerances are concerned because different rolling temperatures, different dimensions of the rolling stock and different starting textures for the subsequent heat treatment will result (consequently also low annular ring weights with high grade steel approximate ly 300 kilograms maximum.

8. All auxiliary devices such as guiding means, electric measuring and control means, for instance, for loop formers, have to be increased and improved with regard to number and quality in such installatrons.

9. Inasmuch as the employment of small roller diameters generally is advantageous, such small roller diameters are also employed in high grade steel trains. However, the starting difliculties (idling periods and disorders) inherent to the changed grasping angle have to be put up with with such material which as for instance fast working steel, do not have a good feel (griffig).

For the above mentioned reasons, rolling trains for high grade metallic substances are considerably more expensive with regard to the specific investment cost per ton production, in operation and in maintenance. The hourly output and ring weights we well as the possible exploitation of time are considerably less. The working condition for simultaneously smallest tolerances, high surface quality and economic operation can with different material and/or dimensions in 100 percent be reproduced or repeated. It is here where the present invention starts.

The rolling method for producing wire or other rodshaped rolling stock of high grade steel and other high grade metallic substances is carried out while employing rolling sets the pressure of which is alternately effected in directions offset by 90. Furthermore, oval calibers on one handand upsetters and round calibers on the other hand are to be employed. In conformity with the present invention, a plurality of non-offset oval passes are followed by a plurality of upsetting and round passes which, while not being offset with regard to each other, are offset relative to said oval passes by The major number of these oval passes on one hand and of the upsetting and round passes on the other hand will henceforth be termed group. In conformity with the method according to the present invention, preferably round material such as wire and round steel will be processed. It is within the nature of this rolling method that also such cross sections can be produced which approximate round cross sections. This applies in particular to polygonal steels such as twelve-edge steels, octagonal steels and hexagonal steels which have an approximately round cross section and, as is well known to the expert in the field, with otherwise unchanged working operation can be produced by exchanging the rollers during the last pass by changing the round cross section.

Expediently, a group of from two to four oval passes is followed by a corresponding group of upsetting and round passes. A manufacturing plan may provide a plurality of each group so that per each oval pass group there will be obtained one upsetting or round pass group. Preferably, the number of the passes pertaining to a group is three.

The total decrease in the surface of the rolling stock in each pass or caliber group should expediently amount from 25 to 45 percent of the starting cross section prior to the respective group. This decrease in surface is more or less uniformly distributed over the individual passes of the group. The reduction in surface in the individual pass should be below 15 percent and with material which is difficult to transform should be below 12 percent of the starting cross section prior to the individual caliber.

For carrying out the method, a device according to the invention has been found particularly suitable according to which the roller pairs of one group are arranged with parallel roller'axles in a common stand. Furthermore, they should have a common motor with a predetermined speed ratio as drive.

EXAMPLE There will now be described an embodiment of the method according to the present invention in comparison to the method according to the prior art.

The problem to be solved consists in rolling material of the quality Cq 35 (Material No. 1.1 172), high speed working steel (Material No. 1.3343) and heat-resistant and corrosion-resistant valve cone steel (Material No. 1.4873) from a 10.00 millimeter starting diameter to a 5.2 millimeter wire.

METHOD ACCORDING TO THE STATE OF THE ART An eight-stand finishing unit of a wire rolling mill is available for the rolling operation. The said unit comprises eight individually controlled horizontal stands while the rolling stock is twisted between the individual stands. There is obtained a medium surface decrease per stand of approximately 14 percent. The exit speed for the rolling stock which could, with non-alloyed material be at 30 meters per second, had to be reduced for the higher alloyed material to 24 or 20 meters per second. The time exploitation factor during any rolling hour during which all three qualities had to be rolled was at 50 percent. The material output reached 81 percent. These relatively low values are the result of test rollings and the post-setting of the roller position when shifting over from one material quality to another one. In spite of careful setting operations, with the finished material all three types of materials obtained the following maximum and minimum dimensions:

5.36 millimeter diameter maximum to 5.09 millimeter minimum. The surface roughness individually reached maximum values of 3811. (medium rough depth according to German industrial standard DIN 4763). A portion of the production of cold upset wire had to be degraded to material II in view of rolling grooves.

WORKING OPERATION ACCORDING TO THE METHOD OF THE PRESENT INVENTION In FIG. 1 the roller stands are arranged in a horizontal-vertical arrangement. The horizontal stands are designated with the reference numeral 1 and the vertical stands are designated with the reference number 3. Each stand has three adjustable pairs of rollers which in the horizontal stand are designated with the reference numeral 2 and in the vertical stand are designated with the reference numeral 4. The drive for these roller trains is effected by four motors 7. Each motor through a transmission 6 and through the intervention of wellknown driving spindles, drives three pairs of rollers 2, 4. Between the horizontal stand and the vertical stand there is moved a slack section 5 (Schlinke) or pull compensation.

FIG. 2 illustrates in conformity therewith the calibrating diagram for a four-stand wire finishing unit from 10 millimeters diameter to 5 millimeters diameter. The shape sequence is multiple-oval and multiple upset/round while each oval profile is formed in three passes 11, 12, 13; 31, 32, 33, and the round profile through the intervention of pre-upsetters is likewise formed in three passes 21, 22, 23; 41, 42, 43. The oval groups 11, 12, 13; 31, 32, 33 as well as the upsetter/round groups 21, 22, 23; 41, 42, 43 are likewise associated with a stand. Within these two profile groups, rolling takes place in fixedly predetermined transmission stages (light pull) whereas between these two profile groups the rolling is effected with a slack portion (pull compensation). The change-over from one wire dimension to another wire dimension is made possible by inserting, transferring and withdrawing of roller pairs. Thus, for instance, when rolling the 5.0 millimeter diameter, the last two stands are operated with six passes 31-43. When rolling from 6.5 millimeter diameter, however, the last two stands are operated only with two passes (31 and 6.5 finish caliber) as is the case with individual drive. The different surface staging from oval to round stand can be adjusted with the con trollable direct current motors. The exit speed from the last one (43) amounts to 45 meters per second. It is retained without any changes regardless of whether a non-alloyed cold upset steel (Cq 35, Material No. 1.1 I72), a high speed working steel (Material No. 1.3343) or a heat and corrosion-resistant valve cone steel (Material No. 1.4873) is being rolled.

The average decrease in surface per stand amounts to 27 percent. Results during an operation of a typical one hour rolling operation are as follows:

Time using factor 83 percent Discharge of material 94 percent These favorable results have been obtained by the elimination of test rolling and by the elimination of waste. The maximum or minimum dimensions reached 5 .26 and 5 18 millimeters diameter. The surface quality is obtained by means of the Perth-O-Meter and resulted in a maximum of 18 1.. Waste by tears and over-rolling did not occur. Similarly, no degrading of an individual roller was required. The invention, as is obvious from the above, results in the following advantages:

The number of the driving motors with electric control and setting devices is reduced (from eight to four). 7

The space requirement of this finishing unit is reduced by about 40 percent.

The decrease in the surface per stand which, with the heretofore common rolling method for high grade steel, is limited to a maximum of 15 percent Stahl und Eisen, 84 (1964) Issue 26, pages 1740/1756 and Stahl und Eisen 86 (1966) Issue 14, pages 877/887, may with the rolling method according to the invention be increased to twice the amount, approximately 30 percent per stand.

Thus, whereas on one hand for a stand with its, for instance, two or three commonly driven pairs of rollers, the decrease in the surface of the rolling stock can per stand be kept greater than with heretofore customary rolling methods, the decrease in surface from pass to pass is considerably less. According to the present example in which each stand with :its three roller pairs brings about a surface decrease of 30 percent, the individual pass brings about only a surface decrease of 10 percent. This surface decrease, which is reduced over heretofore known rolling methods without additional expenses, results in considerable advantages from a rolling technical standpoint. Surface decrease will from a rolling technical standpoint resuit in considerable ad vantages. 'Ihus, without reducing the passing conditions, without expensive guiding, measuring and control devices, the roller diameters are reduced. The reduction in the gripping angle or limiting angle of rolling does not result in any setbacks because the individual roller stand has to perform only a slight deforming operation. In view of this change in the deforming output to be performed by individual roller pairs, for instance, the transfer to the roller discs is structurally simplified. Inasmuch as roller pressures and torque (as a result of the reduced decrease in height per pass) are lowered, the driving and bearing questions can be more easily mastered which, with the customary rolling method for rod-shaped rolling stock of high heat resistance, could heretofore not be mastered in an operational safe manner.

The rolling speed and thus the hourly output of the train is increased by more than 40 percent. The extent of the capital investment and output reducing test rolling operations are clearly reduced and occur only with important changes in the dimensions.

According to the rolling method of the invention, changes in the employed material can be effected without practically interrupting the operation. Also the rolling tolerances are improved.

The surface quality is increased, waste and collection of rolling material ll selection is reduced.

The working operations for simultaneously high quality of the rolling stock and an economic operation can precisely be repeated even when changing to different materials and/or dimensions.

Capital service, personnel and other operational costs, as well as servicing costs, are considerably reduced with the method according to the present invention.

It is, of course, to be understood that the present invention is, by no means, limited to the particular method and arrangement set forth above but also comprises any modifications within the scope of the appended claims.

What we claim is:

l. A method of making wire or other rod-shaped rolling stock of circular and nearly circular cross-section, especially of high grade steel and other high grade metallic substances, which includes the step'of carrying out a plurality of successive oval passes not offset with regard to each other, and subsequently at 90 offset to said oval passes carrying out a plurality of compression or round passes not offset with regard to each other.

2. A method according to claim 1, in which the plurality of oval passes comprises from two to four oval passes, and in which the plurality of compression or round passes likewise comprises from two to four passes.

3. A method according to claim 1, in which each the plurality of oval passes and the plurality of compression or round passes form a caliber group, and in which by means of each caliber group in toto the surface of the material being processed is reduced by from 25 to 45 percent while said surface reduction is being distributed over the individual passes of the same caliber group.

4. A method according to claim 3, in which the surface reduction per each individual pass is less than 15 percent.

5. A method according to claim 3, in which with material which is relatively difficult to deform the surface reduction is per each pass kept below 12 percent.

6. A method according to claim 1, of making rolling stock having a nearly circular, especially polygonal cross-section, which includes the step of producing said nearly circular cross-section from the circular crosssection during the last pass of the pertaining caliber group.

7. A roller train for making wire and other rodshaped rolling stock of circular and nearly circular cross-section, especially of high grade steel and other high grade metallic substances, which includes: a plurality of roller stands respectively arranged in series in spaced relationship to each other and comprising horizontal and vertical roller stands alternating with each other, a plurality of groups of rollers respectively adjustably supported by said roller stands, each of said groups including a plurality of roller pairs having parallel roller axes and being arranged in a common stand, and motor means drivingly connected to said rollers.

8. A roller train according to claim 7, in which the roller pairs of each group are drivingly connected to motor means common thereto. 

1. A method of making wire or other rod-shaped rolling stock of circular and nearly circular cross-section, especially of high grade steel and other high grade metallic substances, which includes the step of carrying out a plurality of successive oval passes not offset with regard to each other, and subsequently at 90* offset to said oval passes carrying out a plurality of compression or round passes not offset with regard to each other.
 2. A method according to claim 1, in which the plurality of oval passes comprises from two to four oval passes, and in which the plurality of compression or round passes likewise comprises from two to four passes.
 3. A method according to claim 1, in which each the plurality of oval passes and the plurality of compression or round passes form a caliber group, and in which by means of each caliber group in toto the surface of the material being processed is reduced by from 25 to 45 percent while said surface reduction is being distributed over the individual passes of the same caliber group.
 4. A method according to claim 3, in which the surface reduction per each individual pass is less than 15 percent.
 5. A method according to claim 3, in which with material which is relatively difficult to deform the surface reduction is per each pass kept below 12 percent.
 6. A method according to claim 1, of making rolling stock having a nearly circular, especially polygonal cross-section, which includes the step of producing said nearly circular cross-section from the circular cross-section during the last pass of the pertaining caliber group.
 7. A roller train for making wire and other rod-shaped rolling stock of circular and nearly circular cross-section, especially of high grade steel and other high grade metallic substances, which includes: a plurality of roller stands respectively arranged in series in spaced relationship to each other and comprising horizontal and vertical roller stands alternating with each other, a plurality of groups of rollers respectively adjustably supported by said roller stands, each of said groups including a plurality of roller pairs having parallel roller axes and being arranged in a common stand, and motor means drivingly connected to said rollers.
 8. A roller train according to claiM 7, in which the roller pairs of each group are drivingly connected to motor means common thereto. 